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fork offsett for custom yokes

Posted: Thu Jan 10, 2013 11:35 am
Author: woody1968
Hi I am a little green with the terminology but I am fitting a set of upside down forks to my Z900 and have found a couple of engineering companies that can make the custom yoke set for my bike but they are asking me for the offset for the forks from the head stock to the fork legs I want to have??
this means not a lot to me but I see you have fitted non stock forks to your bike, what distance am I looking for please?
if you can help that would be great

regards

John

Posted: Thu Jan 10, 2013 12:29 pm
Author: Gus
Hope this may explain things for you

Image



Cheers

Gus

Posted: Thu Jan 10, 2013 12:59 pm
Author: zed1015
Hi Woody.
Gus's diagram along with my reply to your PM should make everything clear. :wink:

Posted: Thu Jan 10, 2013 6:20 pm
Author: LondonZ1
Zed1015's PM may have covered this but I have just fitted custom yokes to a Z900. My bike has a 17" front wheel and I guess yours does to, as it has USD forks. With a smaller wheel, you need less offset than standard to avoid reduced trail and possible instability. The standard offset is 60mm which gives a trail of about 97mm with a 19" front wheel.

I calculated (with assistance from Harris) that a 17" wheel needs about 46mm offset to keep the trail constant assuming no change to the angle of the front forks. I bought yokes from Japan which have a 40mm offset, which gives slightly more trail than standard with a 17" wheel. This should in theory make the steering slower but the reduced inertia of modern wheels will partly counter this.

BTW the forks I have fitted are 800mm long when fully extended. I used Sculpture/Sanctuary yokes which are expensive but beautifully made and come complete with lockstops, taper roller bearings, handlebar brackets, mounting holes for the brake splitter, even the option of using a standard steering lock. I don't know how much you are paying but I would only use a UK firm if they are a lot cheaper than Sanctuary.